Method and apparatus for determining the volume of slugs cut off from irregular bar stock



Sept. 22, 1964 G. L. ANDERSEN 3,149,519

METHOD AND APPARATUS FOR DETERMINING THE VOLUME OF SLUGS CUT OFF FROM IRREGULAR BAR STOCK Filed Jan. 16, 1961 4 Sheets-Sheet 1 CIRCUIT FIGJ.

INVENTOR. GEORGE L. ANDERSEN ATTORNEYS Sept. 22, 1964 G. ANDERSEN METHOD AND APPARATUS FOR DETERMINING THE VOLUME 0F swcs CUT OFF FROM IRREGULAR BAR STOCK 4 Sheets-Sheet 2 Filed Jan. 16, 1961 .INVENTOR. GEORGE LAN D ERSEN ATTORNEY S WIM R p 1964 G. L. ANDERSEN METHOD AND APPARATUS FOR DETERMINING THE VOLUME OF swcs CUT OFF FROM IRREGULAR BAR STOCK 4 Sheets-Sheet 3 Filed Jan. 16, 1961 INVENTOR.

GEORGE LANDERSEN BY w f Q WA ATTORNEYS United States Patent 3,149,519 METHGD AND APPARATUS FOR DETERMINENG THE VOLUME 0F SLUGS CUT QFF FROM IR- REGULAR BAR STOQK George L. Andersen, Birmingham, Mich, assignor, by mesne assignments, to Avis Industrial Corporation, Roseville, Mich, a corporation of Michigan Filed Jan. 16, 1961, Ser. No. 82,790 7 Claims. (Cl. 83-209) The invention relates to method and apparatus for producing slugs of predetermined volume from irregular bar stock and refers more specifically to means for and the method of sensing the cross sectional area of bar stock fed to a cutter and controlling the length of bar stock fed to the cutter in accordance with the sensed cross sectional area so that on operation of the cutter slugs having a predetermined volume are cut from the bar.

In cold forming metal parts from slugs of metal it is essential that the slugs have the proper volume since slugs having less volume than required will produce defective articles while slugs having too large a volume may damage the forming dies.

In the past expensive grinding apparatus has been used to grind bar stock to a predetermined cross section so that slugs having the proper volume could be cut therefrom by cutting the bar at predetermined intervals. Such grinding and measured cutting is expensive, time consuming and tedious.

It is therefore one of the objects of the present invention to provide an improved method of producing slugs of predetermined volume from bar stock of irregular cross section.

Another object is to provide improved means for producing slugs of predetermined volume from bar stock of irregular cross section.

Another object is to provide a method of producing a slug of predetermined volume comprising sensing the cross sectional area of bar stock of irregular cross section and cutting a slug from the bar having a length related to the sensed cross sectional area to provide a slug of predetermined volume.

Another object is to provide a method of producing a slug of predetermined volume set forth above wherein the step of cutting the slug from the bar stock is delayed with respect to the sensing of the cross sectional area so that the sensed cross sectional area is centrally located in the slug cut from the bar whereby the sensed cross sectional area is substantially the average cross sectional area of the slug.

Another object is to provide a method of producing a slug of predetermined volume from bar stock having an irregular cross section comprising sensing a plurality of adjacent cross sectional areas of the bar stock, multiplying the sensed cross sectional areas by a factor determined by the spacing between the areas, adding the plurality of volumes thus obtained until the total volume equals the predetermined volume, and cutting the slug containing the sensed cross sectional areas from the bar.

Another object is to provide means for producing a slug of predetermined volume from bar stock having an irregular cross section comprising a cutter, means for feeding a length of bar stock into the cutter, means for sensing the cross sectional area of the bar stock fed to the cutter, and means for adjusting the length of bar stock fed to the cutter in accordance with the sensed cross sectional area to produce slugs of a given volume on operation of the cutter.

a s e h Another ob ect 18 to provide means for producing a slug of predetermined volume from bar stock as set forth above including delay means for delaying the adjustment of the length of bar fed to the cutter due to sensing of a particular cross sectional area of the bar until a slug having the particular sensed cross sectional area of the bar therein is positioned to be cut from the bar.

Another object is to provide means for producing a slug of predetermined volume from bar stock having an irregular cross section comprising a cutter, means for feeding a length of bar stock into the cutter, a plurality of sensing means for sensing a plurality of adjacent cross sectional areas of the bar, means for multiplying the sensed cross sectional areas by a factor determined by the distance between the cross sectional areas sensed, means for adding the volumes thus obtained, and means for operating the cutter when the added volumes reach a predetermined value representative of a slug of the predetermined volume.

More specifically it is an object of the present invention to provide a method of producing slugs of predetermined volume from bar stock of irregular cross section comprising developing an electric signal representative of the cross sectional area of the bar stock, positioning a stop operable to determine the length of bar stock fed to a cutter in accordance with the developed electric signal, feeding the determined length of bar stock into the cutter and cutting the slug therefrom.

More specifically it is an object of the present invention to provide means for producing slugs of predetermined volume fronrbar stock of irregular cross section comprising means for feeding a length of bar stock into a cutter, a stop positionable to determine the length of bar stock fed into the cutter, electronic means for developing a signal representative of the cross sectional area of the bar stock, and means for positioning the stop in accordance with the developed signal so that the length of bar stock fed into the cutter will produce a slug of predetermined volume on operation of the cutter.

Another object is to provide a method and apparatus for producing slugs of predetermined volume from irregular bar stock which are simple, economical and efficient.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating preferred embodiments of the invention, wherein:

FIGURE 1 is a top view of apparatus for producing slugs of predetermined volume from bar stock having irregular cross section in accordance with the invention.

FIGURE 2 is a side View of the apparatus illustrated in FIGURE 1.

FIGURE 3 is a cross section of the apparatus illustrated in FIGURE 1 taken on the line 33 in FIGURE 1.

FIGURE 4 is a cross section of the apparatus illustrated in FIGURE 1 taken on the line 4-4- in FIGURE 1.

FIGURE 5 is a cross section of the apparatus illustrated in FIGURE 1 taken on the line i5 in FIGURE 1.

FIGURE 6 is a schematic diagram showing in detail parts of the control circuit illustrated in FIGURE 1.

FIGURES 7 and 8 are block diagrams of modified control circuits for use with apparatus similar to that of FIGURES 1-5 for producing slugs of predetermined volume from bar stock having an irregular cross section. With reference to the drawings a specific embodiment of the present invention will now be disclosed.

As shown in FIGURES 1-5, the invention comprises means it) for feeding bar stock 12. into cutter 14. The length of the bar stock 12 fed to cutter 14 during a single cycle of means it) is determined by the spacing means 16. In accordance with the invention the spacing means 16 is controlled by the electronic control circuit 18 shown best in FIGURES 6 and 7.

More specifically the means it for feeding bar stock 12 to cutter 14 comprises base plate 20, gripping means 22 and 24, cylinder and spacing means 16. Base plate 2% may be constructed of metal in the form shown best in FIGURE 1 to provide support for the other members of means It the cutter 14, and the electronic control circuit 18.

The gripping means 22 comprises a frame 28 having rods 39 and 32 journaled therein as shown in FIGURE 3. Rods 39 and 32 support gripping members 34 and 36 therebetween on fixed cross member 33 and slidable cross member 4% respectively, as shown in FIGURE 3. Actuating cylinder 42 is secured to frame 28 as shown. liston rod 44 extends from cylinder 42 through frame 23 and is rigidly secured to member 4% as shown whereby on extension of the piston rod due to actuation of cylinder 42 the gripping members 3 3 and 36 are caused to engage and securely hold bar stock 12 placed therebetween.

The frame 28 of gripping means 22 as shown best in FIGURL 3 is supported on guide plate 46 for sliding movement therewith along guideways 48 which are supported in opening 54} in base plate 2%. Cylinder 26 having piston rod 52 extending therefrom which piston rod is secured to the guide plate 46 by means of pin 54 proides means for moving gripping means 22 along guideways 48. Cylinder 26 is secured to base plate 26 in an opening 56 cut therein by means of pin 58 as shown best in FIGURE 1.

Gripping means 24 is similar to gripping means 22 except that the frame 6% therefor is rigidly secured to the base plate 2% in the position illustrated best in FIGURE 2. Cylinder 62 functions to cause gripping members 64 and as to grip bar stock positioned therebetween when piston rod 68 is extended and to release the bar stock when the piston rod as is retracted in the same manner as described in conjunction with gripping means 22.

Spacing means 1% includes sine bar 7% secured to base plate it? by bridge 7.. for sliding movement transverse to the ads of the bar stock 12 held in gripping means 22 and 24-. Sine bar 74 may be positioned transversely of bar stock 12 by adjusting means 74 which may be actu: ated either manually or by means of the electronic control circuit 18 as will later be seen.

Frame 28 of gripping means 22 is provided with a tapered surface is as shown best in FIGURE 1 operable ItO abut the tapered surface 73 of the sine bar iii on retraction of the piston rod 52. Thus the retraction of piston rod 52 is variably limited by the transverse position of the sine bar is with respect to the bar stock 12.

The operation of the apparatus thus far described is cyclic and may be timed by means of a rotating cam wheel (not shown) which is operable to sequentially open and close hydraulic valves to cylinders 22, 24 and 26 in a predetermined sequence in time with the operation of the cutter 14 as will be readily understood by those in the art.

In sequence of operation of the means it it will first be assumed that bar stock 12 from which a slug has just been cut by cutter 14 is rightly gripped by gripping members and 66 due to extension of piston rod 63 of gripping means 24 and that piston rod 44, of gripping means 22 is extended so that the bar stock is also gripped by gripping means 3 and 36. In addition it will also be assumed that the piston rod 52 is extended so that gripping means 22 abuts forward stop 3%} provided therefor.

Piston rod 44 is then retracted whereby gripping means 3 and 36 release the bar stock. Piston rod 52 i retract-ed to move gripping means 22 into a position whereat the tapered surface 76 of frame 2% abuts the tapered surface 73 of sine bar iii. Piston rod is next extended whereby gripp ng means and 36 grip the bar stock. Piston rod 62'; is then retracts so that the bar stock is released by gripping means 64 and 66 and piston rod d is extended whereby the gripping means 22 and the bar stock gripped thereby is moved forward a distance determined by the distance between the surface '78 of the \sine bar at the centerline of bar stock 12 and the fixed stop Thus a length of bar stock 12 which length is predetermined by the transverse setting of the sine bar 76 is fed into the cutter r4. Piston rod 68 is then extended so that gripping members 64 and 66 also grip the bar stock 12 to firmly hold the bar stock while the predetermined length thereof is removed therefrom by means of cutter 14. l Cutter 14 as shown best in FIGURES 1 and 4- comprises a fixed cutting block 82 having an opening 84 therein through which the bar stock is allowed to pass WlliCll block %2 is held in position in frame 3-6 by convenient means such as blocks 88. Cutter 14 also includes a movable cutting block W also having therein an opening 92 through which the bar stock is permitted to pass. Cutting blocx 92 is movable relative to cutting block 82 to shear slugs from bar stock 12 inserted in cutter 14.

As shown in FIGURE 4 cutter 14 may be operated by reciprocal movement of cam member which is spring loaded in the position shown in FIGURE 4. Movement of cam member 94 toward base plate 20 causes cam follower 96 to move toward the cutting block 92 to shear slugs from bar stock 12. Cutting block 92 is also spring loaded by means l d to return to the position shown in FIGURE 4.

The cam sans 94 may be operated in sequence with the operation of cylinders 25, 42 and 62 by the rotating cam wheel previously mentioned so that cutting of a slug from the bar stock 32 will be accomplished only after a predetermined length thereof has been inserted cutter l4 and the bar stock is firmly held in position for cuttin The electronic control circuit 18 previously mentioned is provided in accordance with the invention to sense the cross sectional area of the bar stock inserted in cutter 14 as determined by the average diameter of the bar stock and to adjust the sine bar 7t laterally in accordance with the sensed cross sectional area so that the length of bar stock inserted in cutter 1 5 during each cycle of operation of means it will provide a slug of predetermined volume on operation of the cutting means l t.

The control circuit 18 as shown partly in block diagram form in FIGURE 1, comprises eight linear variable differential transformers 136-343 positioned angularly about the circumference of the bar stock 12 as shown best in FIGURE 5 which transformers are operable in conjunction with the measuring circuit 192 to develop a signal representative of the cross sectional area of the bar stock 12. The electronic means 18 further includes a mechanical full wave rectifier 1 54 for rectifying the signal developed in the measuring circuit 132, a feed back circuit 106 for stabilizing the signal produced by rectifier 10 i, and a ter network 193 for filtering the stabilized and rectified signal from the rectifier add. A servo-amplifier circuit 119, servo-motor 112 and gear drive 114 operable to position the sine bar it) transversely of the bar stock 12 in accordance with the signal received thereby from the filter network 168 are also provided in control circuit 18.

A portion of the electronic control circuit 18 illusstrated n block diagram form in FIGURE 1 is shown in schematic form in FIGURE 6. The operation of the electronic control circuit 1 5 will become apparent on consideration of the sch matic portion of FIUURE 6. With switch 116 closed power is supplied to the primary coil 11% of transformer through use 122, thus applying alternating voltage to the secondary coils 12 and 126 of transformer 12%.

Secondary coil 126 of transformer 12%, as illustrated in FIGURE 6, supplies voltage to the primary coils 128 through of the individual transformers 136 through 143. The transformers 136 through 143 are provided with movable core members 144 through 152. Each of the transformers 136 through 143 is provided with a pair of secondary coils 153454, 155 156, 15715$, 159-169, 161462, 1163464, 165466 and 167468, respectively. One of the secondary coils of each of the transformers 5 136 through 14-3: is connected in each of the series of coils 169 and Fit as shown.

The transformers 136 through 143 are linear variable differenital transformers and are such that movement of the core members thereof will equally and oppositely change the magnitude of the voltages in the two secondary windings thereof. The direction of change of magnitude of the voltages will depend on the direction of movement of the core.

Thus with the transformers 136 through 14-3 arranged angularly about the bar stock 12 as shown in FIGURE 5, movement radially inwardly of the bar stock of one of the transformers 136 through 143 without a corre sponding radially outward movement of the opposite transformer will produce a variation in the voltage across 29 resistors 17% and 172 in the measuring circuit Hi2. Since the secondary coils of the transformers are connected in series 16% and 171 as shown in FIGURE 6, the total change in the signal across resistors 17% and 172 in measuring circuit 192. will be representative of the variation of the cross sectional area of the bar stock at the point of contact therewith by the transformers arranged as shown in FEGURE 5.

Rectifier 164- as illustrated in FEGURE 6 is a mechanical full wave rectifier which is actuated by circuit 3174: g

znich includes the secondary coil 124 of transformer 12f capacitor 176 and coil 178. The action of rectifier Edd in conjunction with the series connected transformer secondaries 153 through 163 or" the transformers 12-6 through 143 is to produce an output the polarity and magnitude of which depends on the variation of the cross ectionai area of the bar stock from a preselected cross section as will be understood by those familiar with the operation of these devices.

The rectified signal from rectifier 364 is passed through the filter network 1% comprising resistors 1311 and E52 and capacitors 1%, 186 and 188. The rectified and illtered signal which is representative of the cross sectional area of the bar stock at the point of contact of the bar stock with the transformers is then passed to the servoarnplifier lit? where it is amplified to a value to operate the servo-motor 112 which in turn moves the sine bar in through gear drive 11 and actuating means 74 to position the sine bar so that a length of bar stock suicient to provide a slug of predetermined volume having the dianr- K0 eter sensed is fed to the cutter 14.

Feed back means 1% compri log a stabilizing unit tea in conjunction with resistors 19?. and are provided in the electronic circuit 18 to prevent transient conditions from causing erroneous signals from being fed to the servo-amplifier L l Resistors 1% and 1% are provided in series with the secondary coils of the transformers 1.1% through 143 as shown to limit current therethrough. Slide wire 2% in conjunction with movable arm is also provided in series between the series 169 and series 11'1 of secondary coils as shown in FIGURE 6, to provide for setting the zero output position of the rectifier which corresponds to bar stock having a pro determine diameter and a particular settin of sine bar 79.

Slide wire 2% is also provided in series with the secondary coils of the transfor ler 136 through 143 in conjunction With movable arm 2% to balance the voltage produced by the diierent secondary coils of the series 1-5? and 371. Thus the movable arm 2% is driven by ge rive 114 so that it is always positioned to give a zero output from rectifier 1% if the sensed cross sect nal area of the bar stock 12 has not changed between cycles of operation of the apparatus 15 and the cutting of a slug from the bar stock 12 by cutter 14. 7

The actual length of the slug fed to the cutter 14 by means it? for a given variation from a zero voltage difference developed between coil series 169 and 171 may be set by the length control potentiometer 268 which is in series with resistor 210 and in parallel with the resistor since by varying the resistance of resistor 2% the signal across resistor 170 and 172 which is fed to the rectifier 164 and consequently to servo-amplifier 110 is varied.

The servo-amplifier 112, servo-motor 113 and gear drive lid shown in FIGURES 1 and 6 are completely conventional and therefore they will not be discussed in detail.

The transformers 136 through 143, as shown best in FiGURE 5, are supported in circular yoke 212. The cores of the transformers are each mounted on a separate rod 216 having a wear-tip 218 on one end thereof and having a piston 22% on the other end thereof reciprocal in a bore 22-2 in yoke 212. As indicated yoke 212 is provided with a pair of annular hydraulic passages 224 and 2 6 communicating with each of the bores 222 to effect reciprocal movement of the pistons 226, the cores and rods 216 on reversing of the hydraulic pressures within the passages 224 and 226. The coils of the transformers are positioned adjacent the core thereof as shown in FIG- URE 5 so that movemment of the core changes the cou pling of the primary and secondary coils of the transformers to produce the voltage differential between the secondary coils of the transformer previously indicated.

In operation hydraulic fluid is exhausted from chamber 226 and placed in chamber 224 under pressure to cause t 1C wear-tip 213 of the transformers to engage the surface of the bar stock 12 and to remain in engagement thereas the bar stock is fed into the cutter 14. Means may be provided however, such as coil 22%, responsive to the output of the servo-amplifier 112 for actuating conventional switching (not shown) to reversing the hy draulic pressure in chambers 224- and 226 to cause the rod 216 to withdraw the wear-tip 218 from contact with the surface of bar stock 12 on the output of the servo-amplifier being above a predetermined maximum.

Thus when an exceptionally large signal such as that caused by the end of the bar stock passing the transferreers is fed to the servo amplifier, the rods 216 are withdrawn. by reversal of the pressure in the chambers 22.4 and 22! to prevent breaking of the rods by subsequent bar stock inserted in the cutter 14. The coil 228 may also be used to open switch 116 to prevent the return of the rods 21% to their radially inner position before subsequent bar stock is fed into the cutter 14.

in the over-all operation of the apparatus described above it will again be assumed that a slug has been cut from the bar stock 12 by cutter 14 and that the bar stock 12 is tightly gripped by gripping means 22 and 24 with the gripping means 22 positioned against the abutment It will also be assumed that the wear-tips 18 associated with transformers 136 through 143 are engaged with bar stock 12 as shown in FIGURE 5. Switch 16 is assumed closed.

In a cycle of operation, as previously indicated gripping ieans 22 is caused to release the bar stock 12 and to be moved into engagement with the sine bar 7-9 which has been previously positioned laterally of the bar stock 12 so that on subsequent movement of the gripping means 22 into contact with stop 8% a length of bar stock 12 will be fed into cutter 14 which is related to a previously sensed bar diameter to provide a slug of given volume. Gripping means 22 is then caused to re rip the bar stock 12, the gripping means 24 is caused to release the bar stock 12, and gripping means 22 is moved into position abutting stop 80 whereby the bar stock 12 is fed to cutter 14.

As the bar stock 12 is fed to the cutter 1-4 the variation in cross sectional area of the bar stock is sensed by the control circuit 18 in the manner just described to produce an electric signal operable to cause the sine bar 7i? to move transversely of the bar stock 12 in a direction to compensate for the difference in cross sectional area of the bar stock 12. The diiference in the cross sectional area sensed is compensated for by either allowing a longer or shorter length of bar stock to be fed to cutter 14 during the next cycle of operation so that a slug of given volume will always be cut from the bar stock 12 regardless of the irregular cross sectional area thereof on operation of the cutter 14. The cutter 14 is then caused to cut the slug from the bar stock as previously indicated completing the cycle of operation of the apparatus disclosed.

Thus in accordance with the invention a method of producing slugs of given volume from bar stock having an irregular cross sectional area comprising the steps of sensing the cross sectional area of the bar stock and feeding a length of bar stock into a cutter which is so related to the cross sectional area as to produce a. slug of given volume on operation of the cutter.

A modification of the method and apparatus for producing slugs of a predetermined volume from irregular bar stock as set forth above is illustrated in the block diagram of the electronic control circuit 18a shown in FIGURE 7. The control circuit 18:; is similar in every way to the control circuit 18 and in addition includes an amplifier 23% immediately following the filter and a delay device 232 which may for example be a storage tape or drum and read-in and read-out means associated therewith. The output from delay 232 is fed to the servoamplifier lllla.

Thus in accordance with the modification a delay is introduced in the positioning of the sine bar 7d of the spacing means 16 so that the sensed cross section of the bar stock 12. which has caused the positioning of the sine bar 7 ti for a given cycle of operation may be centrally positioned in the slug cut from the bar stock 12 during that cycle of operation. Thus with the modified electronic control circuit 153a the sensed cross sectional area will be more nearly the average cross sectional area of the particular slug whose length is determined thereby.

A second modification 13b of the electronic control circuit 18 is illustrated in FIGURE 8. In the control circuit 18b a series of control circuits such as that shown in FIGURE 8 through the delay means 232 are provided at closely spaced longitudinal intervals along the bar stock 12. Thus a plurality of different cross sectional areas of the bar stock 12 Will be sensed by the electronic control circuit 135.

The signals from the delay means 2352b are passed to individual amplifiers 23 i and are then electronically multiplied in multipliers 23% by factors representative of the distance longitudinally of the bar stock 12 of the sum of half the'distance between the sensed cross sectional area and each of the adjacent cross sectional areas sensed to provide a signal indicative of small volumes or" the bar stock immediately adjacent the cross sectional areas sensed.

The signals from the multipliers are then fed to an electronic adding circuit where the individual signals are combined. On the signal in the adder reaching a predetermined value representative of a slug of predetermined volume the cutter is caused to operate. it will therefore be seen that since the dela means 232;!) is provided in the electronic control circuit 13b that the accuracy in volume of the slugs cut from bar stock 12 will be determined only by the possible spacing of the groups of transformers longitudinally of the bar stock 12.

The drawings and the foregoing specification constitute a description of the improved method and apparatus for producing slugs of predetermined volume from irregular barstock in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. Apparatus for producing slugs having a predetermined volume from bar stock having an irregular cross section comprising, a cutter, bar feeding means located adjacent said cutter for feeding lengths of bar stock into said cutter, a plurality of linear variable differential transformers each including a radially extending rod carrying the transformer core resiliently biased into contact with the bar stock which transformers are located angularly about the bar stock in opposed pairs for sensing the cross sectional area of the bar stock adjacent the length thereof to be fed to the cutter, means for developing an electric signal representative of the cross sectional area sensed, a stop operably associated with said means for feeding lengths of bar stock into said cutter to regulate the length of bar stock fed to the cutter, and means operably associated with the stop for positioning the stop in accordance with the developed electric signal.

2. Structure as claimed in claim 1 wherein said means for developing an electric signal representative of the cross sectional area sensed comprises a measuring circuit, a mechanical rectifier and a filter connected in series to receive the output of said transformers and deliver an output signal to said means for positionin said stop.

3. Structure as claimed in claim 2 wherein said stop comprises a sine bar having a tapered surface positionable transversely of the bar stock operable to abut a similarly tapered surface on said means for feeding the bar stock into said cutter to limit movement thereof in accordance with the adjusted position of the sine bar transversely of the bar stock.

4-. Structure as claimed in claim 3 wherein said means for positioning the stop in accordance with the developed signal comprises a. servo-amplifier, a servo-motor and drive means in series between said filter and said stop.

5. Apparatus for producing slugs having a predetermined volume from bar stock having an irregular cross section comprising, a cutter, bar feeding means located adjacent said cutter for feeding lengths of bar stock into said cutter, a plurality of separate sensing means operably associated with the bar stock extending radially of the bar stock and spaced substantially equally therearound for sensing the cross sectional area of the bar stock at a plurality of spaced apart points therealong, means connected to the sensing means for developing electric signals representative of the areas sensed, means in circuit with the electric signal developing means for delaying said electric signals until said cross sections are within the portion of the bar stock to be removed therefrom to form a slug, means in circuit with the means for delaying the electric signals for individually electrically mulitplying the electric signals by a factor representative of the sum of one-half the distance between the cross sectional area sensed and each of the adjacent sensed cross sectional areas to produce a plurality of electric signals representative of adjacent volumes of said bar stock, means in circuit with the multiplying means for adding the signals representative of volume, and means in circuit with the adding means for actuating the cutter when the added signals reach a value representative of said predetermined volume.

6. Apparatus for producing slugs having a predetermined volume from bar stock having an irregular cross section comprising, a cutter, bar feeding means located adjacent said cutter for feeding lengths of bar stock into said cutter, a plurality of separate sensing means extending radially of the bar stock and spaced substantially equally therearound operably associated with the bar stock for sensing the cross sectional area of the bar stock, means for developing an electric signal representative of the area sensed, means for multiplying the electric signal by a factor representative of the length of bar stock fed to the cutter to produce an electric signal representative of the volume of bar stock passing the sensing means and means operably associated with the multiplying means for 9 actuating the cutter when the value indicated by the multiplying means is representative of a predetermined slug volume.

7. Apparatus for producing slugs having a predetermined volume from bar stock having an irregular cross section comprising, a cutter, bar feeding means located adjacent said cutter for feeding lengths of bar stock into said cutter, a plurality of separate sensing means extending radially of the bar stock and spaced substantially equally therearound for sensing the cross sectional area of the bar stock, means connected to the sensing means for developing an electric signal representative of the area sensed, means in circuit with the electric signal developing means for delaying said electric signal until the cross section the area of which has been sensed is within the portion of the bar stock to be removed therefrom to form a slug, means in circuit with the means for delaying the electric signal for multiplying the electric signal by a fac- 10 tor representative of the length of bar stock fed to the cutter to produce an electric signal representative of the volume of bar stock passing the sensing means and means operably associated with the multiplying means for actuating the cutter when the value indicated by the multiplying means is representative of a predetermined slug volume.

References Cited in the file of this patent UNITED STATES PATENTS 2,417,062 Coake Mar. 11, 1947 2,806,295 Ball Sept. 17, 1957 2,855,627 Prentiss Oct. 14, 1958 2,962,645 Rudolf et al Nov. 29, 1960 2,989,883 Zimsky et al June 27, 1961 3,007,252 Munn Nov. 7, 1961 FOREIGN PATENTS 1,159,825 France Feb. 17, 1958 

1. APPARATUS FOR PRODUCING SLUGS HAVING A PREDETERMINED VOLUME FROM BAR STOCK HAVING AN IRREGULAR CROSS SECTION COMPRISING, A CUTTER, BAR FEEDING MEANS LOCATED ADJACENT SAID CUTTER FOR FEEDING LENGTHS OF BAR STOCK INTO SAID CUTTER, A PLURALITY OF LINEAR VARIABLE DIFFERENTIAL TRANSFORMERS EACH INCLUDING A RADIALLY EXTENDING ROD CARRYING THE TRANSFORMER CORE RESILIENTLY BIASED INTO CONTACT WITH THE BAR STOCK WHICH TRANSFORMERS ARE LOCATED ANGULARLY ABOUT THE BAR STOCK IN OPPOSED PAIRS OF SENSING THE CROSS SECTIONAL AREA OF THE BAR STOCK ADJACENT THE LENGTH THEREOF TO BE FED TO THE CUTTER, MEANS FOR DEVELOPING AN ELECTRIC SIGNAL REPRESENTATIVE OF THE CROSS SECTIONAL AREA SENSED, A STOP OPERABLY ASSOCIATED WITH SAID MEANS FOR FEEDING LENGTHS OF BAR STOCK FED TO THE CUTTER, AND MEANS OPERABLY ASSOCIATED WITH THE STOP FOR POSITIONING THE STOP IN ACCORDANCE WITH THE DEVELOPED ELECTRIC SIGNAL. 